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The First Post-Kepler Brightness Dips of KIC 8462852

Published version
Peer-reviewed

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Authors

Alonso, R 
Ammerman, A 
Armstrong, D 
Ramos, AA 

Abstract

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in October 2015, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor", which persist on timescales from several days to weeks. Our main results so far are: (i) there are no apparent changes of the stellar spectrum or polarization during the dips; (ii) the multiband photometry of the dips shows differential reddening favoring non-grey extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale <<1um, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process.

Description

Keywords

comets: general, stars: activity, stars: individual (KIC 8462852), stars: peculiar

Journal Title

Astrophysical Journal Letters

Conference Name

Journal ISSN

2041-8205
2041-8213

Volume Title

853

Publisher

American Astronomical Society
Sponsorship
Science and Technology Facilities Council (ST/J00541X/1)
Science and Technology Facilities Council (ST/M007626/1)
Science and Technology Facilities Council (ST/N005805/1)
Science and Technology Facilities Council (ST/N000927/1)
Science and Technology Facilities Council (ST/J003344/2)
Science and Technology Facilities Council (ST/K003453/1)